In large commercial buildings, recurring electricity costs for lighting can be more than half of the total energy budget. Consequently, there are considerable economic benefits to be obtained through more efficient lighting techniques. For example, simple devices such as motion sensor switches or light timers are often used to reduce wasted energy by reducing unnecessary lighting.
Long term energy and lighting management in large commercial lighting applications presents greater challenges. Lighting requirements in different areas of a store or manufacturing plant may change as departments move or reorganize. Lighting technologies change over time, delivering improved performance and efficiency. Thus, it may become necessary or desirable to replace obsolete lighting technology with newer technology, or to relocate, enhance, or maintain existing lighting fixtures. Especially as energy costs continue to rise, many existing commercial buildings will eventually consider some form of lighting retrofit or redeployment.
Existing commercial buildings vary widely in age, construction, and intended use, so the available electric power sources may have any of several different voltage levels, and access to that power may be provided using a variety of electrical connection types. Support and mounting techniques will vary. Further, lighting requirements, such as light level, spectrum, and timing, are as diverse as the range of intended uses.
Many large commercial lighting applications depend heavily on fluorescent light fixtures driven by a ballast. The type of ballast determines, for example, the power consumption and optimal type of lamp to be used in the fixture. Along with characteristics of the light fixture itself, such as the geometry of the fixture, heat management, and the shapes of the reflectors, the choice of ballast and lamp largely determine the gross light production, expected maintenance interval, and energy consumption of the fixture. Consequently, effective lighting redeployment may require changing the ballast and/or type of lamp used in the fixture.
Light fixtures having enhanced features are familiar to consumers. For example, light fixtures can include photodetectors or motion detectors. A light fixture can be continuously dimmable, or it may include two or more separately controllable light circuits for lighting that can be completely off, partially on, or fully on. A lighting redeployment may introduce or change the use of such enhanced features to help conserve electrical power.
In a typical prior art light fixture, the ballast and any enhanced features are usually hard wired inside the fixture, and the fixture is hard-wired to building power. So, except for changing the lamp, changes to a typical prior art light fixture may often require services of a relatively highly skilled worker, such as an electrician, and/or replacement of the entire fixture.
Thus, it can be costly to remove and replace existing light fixtures, or even to reposition existing light fixtures. It can also be costly to modify or enhance existing light fixtures with different ballast technology or enhanced features to improve their effectiveness or efficiency. Because of these economic barriers, existing light fixtures tend to remain in place even when they are obsolete or lighting requirements change, resulting in wasted electrical power and lost productivity due to ineffective lighting.
Thus, what is needed is a modular light fixture architecture specially adapted for flexible, cost-effective, and safe retrofit to existing commercial buildings. What is further needed is a modular light fixture architecture specially adapted for flexible, cost-effective, and safe long term maintenance and redeployment in response to changing lighting requirements and improvements in technology.